This invention relatres to a reverberation tone generating apparatus.
The apparatus utilized for adding a reverberation tone to a musical tone can be classified into a mechanical reverberation apparatus, and an electronic circuit utilizing such an analog delay element as a BBD (bucket brigade device) or a CCD (charge coupled device). However, since the former involves various problems regarding constructions and characteristics, the latter type is used in recent years. An example of using a BBD is disclosed in U.S. Pat. No. 4,093,820. In the apparatus utilizing such analog delay element, however, as the reverberation time is elongated, or as the number of serially connected stages of the analog delay elements increases, the output level decreases to greatly decrease the S/N ratio, thus making it impossible to obtain a natural reverberation tone. Moreover, as the reverberation tone time is principally determined by the number of stages of the serially connected analogue delay elements, when the reverberation time is once set, it is difficult to simply change it thereafter.
When adding a reverberation tone to a performed musical tone it is desirable to change the reverberation tone characteristics (length, depth, etc.) in accordance with the frequency band of the performed tone depending upon the tone color or the like of the performed musical tone so as to improve the performance effect.
Where a musical tone is performed in an indoor room, the low frequency component of the performed musical tone has a long reverberation time, while the high frequency component has a short reverberation time period. For this reason, an ideal reverberation tone having uniform reverberation characteristics over entire frequency range can be obtained by varying the reverberation characteristics in accordance with the frequency band of the performed musical tone.
In the prior art reverberation tone generating or adding apparatus, however, a reverberation tone is added to a musical tone signal produced by such a musical tone source as an electronic musical instrument without dividing the signal into different frequency bands so that it has been impossible to add an optimum reverberation tone suitable for the tone color of the performed musical tone or a place of performance.